Engine electromagnetic valve operating device

ABSTRACT

In an engine electromagnetic valve operating device ( 20 ), an intake valve ( 17 ) is opened and closed by means of a first electromagnet ( 21 ), which is fixed to a cylinder head, and a second electromagnet ( 22 ), which is pivotably supported on the cylinder head by a fixed shaft ( 38 ) so as to be capable of swinging, attracting a first attraction face ( 23   b ) and a second attraction face ( 23   c ) respectively of an armature ( 23 ) having one end pivotably supported on the cylinder head by the fixed shaft ( 38 ) so that it can swing and having the other end abutting against a stem ( 18 ) of the intake valve ( 17 ). In this arrangement, by changing the angle between the first and second electromagnets ( 21, 22 ) by swinging the second electromagnet ( 22 ), the amount of lift of the intake valve ( 17 ) can be changed freely. Furthermore, since only at least one of the first and second electromagnets ( 21, 22 ) needs to be made to swing and, moreover, it is unnecessary to move the position of the armature ( 23 ), it is possible to form the electromagnetic valve operating device ( 20 ) compactly.

TECHNICAL FIELD

The present invention relates to an engine electromagnetic valveoperating device for opening and closing a valve by means of an armaturethat is alternately attracted by a first electromagnet and a secondelectromagnet so as to swing.

BACKGROUND ART

An arrangement in which supported on a disk base are an upper disk(armature) and a lower disk (armature) having extremities connected to adrive valve provided in a cylinder head of an engine and having baseends pivotably supported on the disk base, an electromagnet disposedinside the two disks, and a pair of permanent magnets disposed outsidethe two disks, the disk base being movable in a direction perpendicularto an open/close direction of the drive valve, and in which the twodisks are alternately attracted by the electromagnet and the permanentmagnet and made to swing to-and-fro by controlling the passage ofcurrent to the electromagnet thus opening and closing the drive valve,the amount of lift of the drive valve being varied by changing a leverratio of the two disks by moving the disk base by means of an actuator,is known from Patent Publication 1 below.

Patent Publication 1: Japanese Patent Application Laid-open No.2006-22776. DISCLOSURE OF INVENTION Problems to be Solved by theInvention

In the above-mentioned conventional arrangement, since it is necessaryto move the disk base, which supports one electromagnet, two permanentmagnets, and two disks (armatures), by means of the actuator, theoverall electromagnetic valve operating device increases in size, thuscausing the problem that there are significant restrictions on itsdisposition in the confined space within the cylinder head of theengine.

The present invention has been accomplished in the light of theabove-mentioned circumstances, and it is an object thereof to make acompact electromagnetic valve operating device that opens and closes avalve with any amount of lift by means of an electromagnet.

Means for Solving the Problems

In order to attain the above object, according to a first aspect of thepresent invention, there is provided an engine electromagnetic valveoperating device comprising an armature having one end pivotablysupported on an engine main body so as to be capable of swinging andhaving the other end abutting against a stem of a valve, a firstelectromagnet that can attract a first attraction face of the armature,and a second electromagnet that can attract a second attraction face ofthe armature, at least one electromagnet of the first and secondelectromagnets being supported so as to be capable of swinging around afixed shaft whose position is fixed relative to the engine main body.

According to a second aspect of the present invention, in addition tothe first aspect, the one electromagnet causes the valve to lift, anddefines the amount of lift of the valve.

According to a third aspect of the present invention, in addition to thefirst or second aspect, the device comprises a pair of valve springs forurging the armature to a neutral position, a spring seat supporting onevalve spring being fixed to the engine main body and a spring seatsupporting the other valve spring moving in response to swinging of theone electromagnet.

According to a fourth aspect of the present invention, in addition tothe third aspect, the other valve spring and the spring seat supportingthe valve spring are disposed on the outer periphery of the stem of thevalve, and the spring seat is integrally connected to and moves with theone electromagnet.

According to a fifth aspect of the present invention, in addition to anyone of the first to fourth aspects, the armature is pivotably supportedvia the fixed shaft.

According to a sixth aspect of the present invention, in addition to thefifth aspect, the other electromagnet of the first and secondelectromagnets is provided with a fixing part for fixing the fixedshaft.

According to a seventh aspect of the present invention, in addition tothe first aspect, the device comprises a first valve spring for urgingthe valve in a valve-closing direction and a second valve spring forurging the valve in a valve-opening direction, the second valve springurging a lever provided on the one end side of the armature.

According to an eighth aspect of the present invention, in addition tothe seventh aspect, the one electromagnet comprises a lever provided onone end side via which the electromagnet is pivotably supported on thefixed shaft, an urging force of the second valve spring on the one endside acting on the lever of the armature, and an urging force of thesecond valve spring on the other end side acting on the lever of the oneelectromagnet.

According to a ninth aspect of the present invention, in addition to theeighth aspect, at least parts of the lever of the armature and the leverof the one electromagnet overlap when viewed in a cylinder linedirection.

According to a tenth aspect of the present invention, in addition to theeighth or ninth aspect, a guide rod having one end pivotably supportedon the lever of the armature and having a first spring seat provided atthe other end runs through a second spring seat provided in the lever ofthe one electromagnet, and one end and the other end of the second valvespring supported on the outer periphery of the guide rod abut againstthe first spring seat and the second spring seat respectively.

According to an eleventh aspect of the present invention, in addition toany one of the eighth to tenth aspects, an actuator making the oneelectromagnet swing drives the other end side of the electromagnet.

A cylinder head 12 and a head cover 13 of embodiments correspond to theengine main body of the present invention, an intake valve 17 of theembodiments corresponds to the valve of the present invention, firstelectromagnets 21 of the embodiments correspond to the otherelectromagnet of the present invention, second electromagnets 22 of theembodiments correspond to the one electromagnet of the presentinvention, an inside block member 27 of the embodiments corresponds tothe fixing part of the present invention, and a first valve spring 47and a second valve spring 51 of the embodiments correspond to the valvespring of the present invention.

EFFECTS OF THE INVENTION

In accordance with the first aspect of the present invention, since thefirst and second electromagnetics respectively attract the firstattraction face and the second attraction face of the armature havingone end pivotably supported so that it can swing around the fixed shaftwhose position is fixed relative to the engine main body and having theother end abutting against the stem of the valve, the amount of lift ofthe valve can be changed freely by making at least one of the first andsecond electromagnets swing. Furthermore, since only at least one of thefirst and second electromagnets needs to be made to swing and, moreover,it is unnecessary to move the position of the armature, it is possibleto form the electromagnetic valve operating device compactly. Inparticular, since the amount of lift of the valve is varied by makingthe one of the electromagnets swing, the electromagnetic valve operatingdevice can be made compact in the axial direction of the valve.

Furthermore, in accordance with the second aspect of the presentinvention, since the electromagnet that swings makes the valve lift anddefines the amount of lift of the valve, not only is it possible toreliably open the valve, but it is also possible to vary the amount oflift of the valve while suppressing any degradation in collision noisewhen the valve closes.

Moreover, in accordance with the third aspect of the present invention,since, among the pair of valve springs for urging the armature to theneutral position, the spring seat supporting one of the valve springs isfixed to the engine main body, and the spring seat supporting the othervalve spring is moved in response to swinging of the one electromagnet,even if the engine stops, regardless of the swing position of the oneelectromagnet at that time, the armature is prevented from being greatlydisplaced from the neutral position, and it is possible to reliablyattract the armature by the first electromagnet or the secondelectromagnet when the engine is started.

Furthermore, in accordance with the fourth aspect of the presentinvention, since the other valve spring and the spring seat supportingthe valve spring are disposed on the outer periphery of the stem of thevalve, not only is it possible to make the electromagnetic valveoperating device compact, but it is also possible to reliably urge thearmature to the neutral position since the spring seat is connectedintegrally to the one electromagnet and moves in response to swinging ofthe one electromagnet.

Moreover, in accordance with the fifth aspect of the present invention,since the one electromagnet and the armature are pivotably supported onthe same fixed shaft, the positional relationship between the oneelectromagnet and the armature attracted to the electromagnet isunchanged even if the electromagnet swings, and it is easy to controlthe attraction faces of the electromagnet and the armature.

Furthermore, in accordance with the sixth aspect of the presentinvention, since the fixing part via which the fixed shaft is fixed isprovided in the other electromagnet among the first and secondelectromagnets, the positional relationship between the otherelectromagnet and the armature is stabilized, and not only is it easy tocontrol the attraction faces of the other electromagnet and thearmature, but it is also unnecessary to separately ensure that there isa member on which the fixed shaft is provided.

Moreover, in accordance with the seventh aspect of the presentinvention, since among the first valve spring for urging the valve in avalve-closing direction and the second valve spring for urging it in avalve-opening direction, the second valve spring urges the leverprovided on the one end side via which the armature is pivotablysupported on the fixed shaft, it is possible to eliminate the necessityfor disposing the second valve spring on a line extended from the stemof the valve, thereby reducing the size of the electromagnetic valveoperating device.

Furthermore, in accordance with the eighth aspect of the presentinvention, since the urging force from one end of the second valvespring and the urging force from the other end thereof act on the leverprovided on one end side of the armature and the lever provided on oneend side of the one electromagnet respectively, the armature can be madeto swing by means of the resilient force of the second valve spring inresponse to swinging of the one electromagnet; even if the engine stops,regardless of the swing position of the one electromagnet at that time,the armature is prevented from being greatly displaced from the neutralposition, and it is possible to reliably attract the armature by thefirst electromagnet or the second electromagnet when the engine isstarted.

Moreover, in accordance with the ninth aspect of the present invention,since the disposition is such that at least parts of the lever of thearmature and the lever of the one electromagnet overlap when viewed inthe cylinder line direction, it is possible to reduce the size of theelectromagnetic valve operating device.

Furthermore, in accordance with the tenth aspect of the presentinvention, since the guide rod having one end pivotably supported on thelever of the armature and having the first spring seat provided on theother end runs through the second spring seat provided on the lever ofthe one electromagnet, and one end and the other end of the second valvespring supported on the outer periphery of the guide rod are made toabut against the first spring seat and the second spring seatrespectively, it is possible to reduce the number of components byutilizing the guide rod as a support member for the second valve spring.

Moreover, in accordance with the eleventh aspect of the presentinvention, since the actuator making the one electromagnet swing drivesthe other end side of the electromagnet, that is, the side that isdistant from the fixed shaft pivotably supporting the electromagnet, itis possible to reduce the burden on the actuator and enhance thepositioning precision of the swing position of the electromagnet.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of an engine cylinder head provided with anelectromagnetic valve operating device related to a first embodiment(first embodiment).

FIG. 2 is an enlarged view of an essential part of FIG. 1 (firstembodiment).

FIG. 3 is an exploded perspective view of the electromagnetic valveoperating device (first embodiment).

FIG. 4 is an exploded perspective view of a swinging part of a secondelectromagnet (first embodiment).

FIG. 5 is a diagram for explaining the operation (neutral state) at atime of low lift and at a time of high lift (first embodiment).

FIG. 6 is a diagram for explaining the operation (maximum lift state) ata time of low lift and at a time of high lift (first embodiment).

FIG. 7 is a sectional view of an engine cylinder head provided with anelectromagnetic valve operating device related to a second embodiment(second embodiment).

FIG. 8 is an enlarged view of an essential part of FIG. 7 (secondembodiment).

FIG. 9 is a view from arrowed line 9-9 in FIG. 8 (second embodiment).

FIG. 10 is an exploded perspective view of the electromagnetic valveoperating device (second embodiment).

FIG. 11 is an exploded perspective view of a second electromagnet andits swinging part (second embodiment).

FIG. 12 is a diagram for explaining the operation (neutral state) at atime of low lift and at a time of high lift (second embodiment).

FIG. 13 is a diagram for explaining the operation (maximum lift state)at a time of low lift and at a time of high lift (second embodiment).

EXPLANATION OF REFERENCE NUMERALS AND SYMBOLS

-   -   12 Cylinder head (engine main body)    -   13 Head cover (engine main body)    -   17 Intake valve (valve)    -   18 Stem    -   21 First electromagnet (other electromagnet)    -   22 Second electromagnet (one electromagnet)    -   23 Armature    -   23 b First attraction face    -   23 c Second attraction face    -   23 d Lever    -   27 Inside block member (fixing part)    -   34 d Lever    -   38 Fixed shaft    -   44 Spring seat    -   47 First valve spring (valve spring)    -   49 Spring seat    -   51 Second valve spring (valve spring)    -   43 Actuator    -   150 Guide rod    -   151 First spring seat    -   152 Second spring seat    -   153 Second valve spring

BEST MODE FOR CARRYING OUT THE INVENTION

Modes for carrying out the present invention are explained below byreference to the attached drawings.

Embodiment 1

FIG. 1 to FIG. 6 show a first embodiment of the present invention.

As shown in FIG. 1, a cylinder head 12 is joined to a top face of anengine cylinder block 11, and a head cover 13 is joined to a top face ofthe cylinder head 12. An intake port 14 is formed in the cylinder head12, and a stem 18 of an intake valve 17 for opening and closing a valvehole 16 via which the intake port 14 opens in a combustion chamber 15 isslidably guided by a valve guide 19 provided in the cylinder head 12.

As shown in FIG. 1 to FIG. 4, an electromagnetic valve operating device20 for opening and closing a pair of the intake valves 17 with the sametiming and the same amount of lift includes a pair of firstelectromagnets 21, a pair of second electromagnets 22, a pair ofarmatures 23, and a pair of urging rods 24.

The first electromagnets 21 include a core 25 formed by laminating alarge number of steel sheets, a pair of coils 26 wound around four coilgrooves 25 a formed in the core 25, an inside block member 27superimposed on the inner end of the core 25, and an outside blockmember 28 superimposed on the outer end of the core 25, the inside blockmember 27, the core 25, and the outside block member 28 being integrallysecured by means of four bolts 29. The first electromagnets 21 are fixedto the cylinder head 12 by securing three mounting arms 27 a of theinside block member 27 to a mounting portion 12 a of the cylinder head12 by bolts 30 and securing three mounting arms 28 a of the outsideblock member 28 to a mounting portion 12 b of the cylinder head 12 bybolts 31.

The second electromagnets 22 include a core 32 formed by laminating alarge number of steel sheets, a pair of coils 33 wound around four coilgrooves 32 a formed in the core 32, an inside block member 34superimposed on the inner end of the core 32, and an outside blockmember 35 superimposed on the outer end of the core 32, the inside blockmember 34, the core 32, and the outside block member 35 being integrallysecured by means of four bolts 36. The inside block member 34 isprovided with two hinge arms 34 a and two link arms 34 b, and theoutside block member 35 is provided with three spring seat support arms35 a.

The armatures 23 are plate-shaped members; two hinge arms 23 a areprovided at the inner end, and two rollers 37 are rotatably and axiallysupported at the outer end. A fixed shaft 38 is press-fitted into thethree mounting arms 27 a of the inside block member 27 of the firstelectromagnets 21, and the two hinge arms 23 a of the armatures 23 andthe two hinge arms 34 a of the inside block member 34 of the secondelectromagnets 22 are fitted around the outer periphery of the fixedshaft 38 in a relatively rotatable manner. The armatures 23 and thesecond electromagnets 22 are therefore pivotably supported so that theycan swing around the fixed shaft 38 independently from each other. Thefixed shaft 38 referred to here means that its position does not moverelative to the cylinder head 11, and it may rotate at the sameposition.

Two link arms 39 a provided on a control shaft 39 rotatably supported onthe cylinder head 12 and the two link arms 34 b of the inside blockmember 34 of the second electromagnets 22 are pivotably supported atopposite ends of a control link 40 via pins 41 and 42 respectively.Therefore, when the control shaft 39 is rotated to-and-fro by means ofan actuator 43 such as an electric motor, it makes the secondelectromagnets 22 swing around the fixed shaft 38 via the control link40.

A cylindrical spring seat 44 is slidably fitted into a guide recess 12 cformed in the cylinder head 12 coaxially with the intake valve 17, and apin 45 provided on the spring seat 44 engages with an oblong hole 35 bprovided in the extremity of the spring seat support arm 35 a of theoutside block member 35 of the second electromagnets 22. Therefore, whenthe second electromagnets 22 swing, this is tracked by the spring seat44 moving vertically along the guide recess 12 c. The reason for thearrangement in which it is the oblong hole 35 b that the pin 45 providedin the spring seat support arm 35 a engages with is because the springseat support arm 35 a of the outside block member 35 swings around thefixed shaft 38 whereas the spring seat 44 moves linearly along the guiderecess 12 c.

A first valve spring 47 is provided in a compressed state between thespring seat 44 and a spring seat 46 provided at the upper end of thestem 18 of the intake valve 17. The first valve spring 47 urges theintake valve 17 in a valve-closing direction (upward), and the urgingforce makes the upper end of the stem 18 of the intake valve 17 abutagainst the roller 37 of the armature 23.

The urging rod 24, which is disposed coaxially with the stem 18 of theintake valve 17, is slidably supported in a rod guide 48 provided on asupport portion 13 a of the head cover 13. A second valve spring 51 isprovided in a compressed state between a spring seat 49 formedintegrally with the rod guide 48 and a spring seat 50 provided on alower part of the urging rod 24, and the lower end of the urging rod 24,which is urged downward by the second valve spring 51, abuts against theroller 37 of the armature 23. A hydraulic cushion mechanism 52 forcushioning the impact when the intake valve 17 is seated is provided inan upper part of the rod guide 48.

The operation of the first embodiment of the present invention havingthe above-mentioned arrangement is now explained.

When the second electromagnets 22 are made to swing around the fixedshaft 38 via the control shaft 39 and the control link 40 by theactuator 43, the angle formed between the lower face of the firstelectromagnets 21 fixed to the cylinder head 12 and the upper face ofthe second electromagnets 22 that have been made to swing changes. FIG.5 (A) corresponds to a case in which the angle is a small angle α andthe intake valve 17 is driven with a small amount of lift, and FIG. 5(B) corresponds to a case in which the angle is a large angle β and theintake valve 17 is driven with a large amount of lift.

When the first and second electromagnets 21 and 22 are not energized,regardless of whether the second electromagnets 22 are in a low liftstate or in a high lift state, the armature 23 always stops at asubstantially neutral position of the wedge-shaped space formed betweenthe first and second electromagnets 21 and 22. The reason therefor is asfollows.

In the low lift state, the armature 23 is pushed upward by the stem 18of the intake valve 17, which is urged upward by the first valve spring47, and is pushed downward by the urging rod 24, which is urged downwardby the second valve spring 51, and the armature 23 stops at the neutralposition at which the upward-pushing force and the downward-pushingforce are balanced. The resilient forces of the first and second valvesprings 47 and 51 are adjusted so that at the neutral position thearmature 23 stops substantially midway between the first and secondelectromagnets 21 and 22.

When the second electromagnets 22 descend from this state to the highlift state, since the spring seat 44, which supports the lower end ofthe first valve spring 47, descends together with the secondelectromagnets 22, the first and second valve springs 47 and 51 expandequally. As a result, the armature 23 swings downward from the low liftstate, and in the high lift state it also stops at a neutral positionthat is in substantially the middle of the space between the first andsecond electromagnets 21 and 22.

If the lower end of the first valve spring 47 were to be supported onthe cylinder head 12 so that it could not move, in the high lift stateeven if the second electromagnets 22 were to swing downward the armature23 would not move from the position in the low lift state, and theclearance between the armature 23 and the second electromagnets 22 wouldincrease relative to the clearance between the armature 23 and the firstelectromagnets 21, which would be a problem.

In such an arrangement, if when the engine stops the armature 23 doesnot stop at around the midpoint between the first and secondelectromagnets 21 and 22, in a cylinder with a timing in which at themoment of starting the engine the second electromagnets 22 are energizedand the armature 23 is attracted, a large attraction force would berequired for the second electromagnets 22, which are at an increaseddistance from the armature 23, and problems such as an increase in thedimensions of the second electromagnets 22 and an increase in powerconsumption would occur.

In contrast thereto, in the present embodiment, since the armature 23reliably stops substantially midway between the first and secondelectromagnets 21 and 22 when the engine stops, whichever of the firstand second electromagnets 21 and 22 is first energized when the engineis started, an especially large attraction force is not required, andthe above-mentioned problems are therefore eliminated.

Furthermore, not only is it possible to achieve a compact size since thefirst valve spring 47 and the spring seat 44 are disposed on the outerperiphery of the stem 18 of the intake valve 17, but since the springseat 44 is connected to the second electromagnets 22 via the pin 45 andthe oblong hole 35 b it is also possible to make the spring seat 44 movein response to swinging of the second electromagnets 22, thus reliablyurging the armature 23 to the neutral position regardless of the swingposition of the second electromagnets 22.

When the first electromagnets 21 are energized, a first attraction face23 b of the armature 23 is attracted to the lower face of the firstelectromagnets 21, and the armature 23 is thereby swung upward aroundthe fixed shaft 38, thus pushing the urging rod 24 upward by means ofthe roller 37 while compressing the second valve spring 51. At the sametime as this, the intake valve 17, whose stem 18 is pushed upward bymeans of the resilient force of the first valve spring 47, is seated onthe valve hole 16 and closed. The dimensional relationships between theparts are set so that the first attraction face 23 b of the armature 23comes into intimate contact with the lower face of the firstelectromagnets 21 in a state in which the intake valve 17 is closed. Theimpact at the moment when the intake valve 17 is seated on the valvehole 16 is cushioned by the hydraulic cushion mechanism 52, whichsuppresses upward movement of the upper end of the urging rod 24.

When the first electromagnets 21 are de-energized and the secondelectromagnets 22 are energized in a state in which the intake valve 17is closed, a second attraction face 23 c of the armature 23 is attractedto the upper face of the second electromagnets 22. The armature 23swings downward around the fixed shaft 38 and pushes the stem 18downward via the roller 37 while compressing the first valve spring 47,thus opening the intake valve 17. In this process, the urging rod 24descends so as to follow the armature 23 by virtue of the resilientforce of the second valve spring 51. When the second attraction face 23c of the armature 23 comes into intimate contact with the upper face ofthe second electromagnets 22, the amount of lift of the intake valve 17becomes a maximum amount of lift, and as shown in FIG. 6 the maximumamount of lift is freely changed by the swing position of the secondelectromagnets 22.

Since the second electromagnets 22 and the armature 23 swing around thecommon fixed shaft 38, in both the low lift state of FIG. 6 (A) and thehigh lift state of FIG. 6 (B), the second attraction face 23 c of thearmature 23 can be made to come to intimate contact with the upper faceof the second electromagnets 22, and it becomes easy to control theupper face of the second electromagnets 22 and the second attractionface 23 c of the armature 23. Furthermore, since the fixed shaft 38 isprovided on the first electromagnets 21, which are fixed to the cylinderhead 11, not only is it unnecessary to ensure a location on the cylinderhead 11 for providing the fixed shaft 38, but also the positionalrelationship between the first electromagnets 21 and the armature 23 isstabilized, and control of the lower face of the first electromagnets 21and the first attraction face 23 b of the armature 23 becomes easy.

In this way, by changing the swing position of the second electromagnets22, the maximum amount of lift of the intake valve 17 can be variedfreely, and by changing the timing with which the first and secondelectromagnets 21 and 22 are energized and de-energized, the valvetiming of the intake valve 17 can be varied freely. In this process,since only the position of the second electromagnets 22 need be changed,without the positions of the first electromagnets 21 and the armature 23being changed, compared with an arrangement in which all of the firstand second electromagnets 21 and 22 and the armature 23 are moved, theelectromagnetic valve operating device 20 can be made more compact.Moreover, since the first electromagnets 21, which restrict the valveclosing position of the intake valve 17, is fixed so that it cannotmove, the intake valve 17 can be seated with good precision.

Embodiment 2

FIG. 7 to FIG. 13 show a second embodiment of the present invention.

As shown in FIG. 7, a cylinder head 12 is joined to a top face of anengine cylinder block 11, and a head cover 13 is joined to a top face ofthe cylinder head 12. An intake port 14 is formed in the cylinder head12, and a stem 18 of an intake valve 17 for opening and closing a valvehole 16 via which the intake port 14 opens in a combustion chamber 15 isslidably guided by a valve guide 19 provided in the cylinder head 12.

As shown in FIG. 7 to FIG. 11, an electromagnetic valve operating device20 for opening and closing a pair of the intake valves 17 with the sametiming and the same amount of lift includes a pair of firstelectromagnets 21, a pair of second electromagnets 22, and a pair ofarmatures 23.

The first electromagnets 21 include a core 25 formed by laminating alarge number of steel sheets, a pair of coils 26 wound around four coilgrooves 25 a formed in the core 25, an inside block member 27superimposed on the inner end of the core 25, and an outside blockmember 28 superimposed on the outer end of the core 25, the inside blockmember 27, the core 25, and the outside block member 28 being integrallysecured by means of four bolts 29. The first electromagnets 21 are fixedto the cylinder head 12 by securing three mounting arms 27 a of theinside block member 27 to a mounting portion 12 a of the cylinder head12 by bolts 30 and securing three mounting arms 28 a of the outsideblock member 28 to a mounting portion 12 b of the cylinder head 12 bybolts 31.

The second electromagnets 22 include a core 32 formed by laminating alarge number of steel sheets, a pair of coils 33 wound around four coilgrooves 32 a formed in the core 32, an inside block member 34superimposed on the inner end of the core 32, and an outside blockmember 35 superimposed on the outer end of the core 32, the inside blockmember 34, the core 32, and the outside block member 35 being integrallysecured by means of four bolts 36. The inside block member 34 isprovided with four hinge arms 34 a and four levers 34 c extending fromthese hinge arms 34 a.

The two armatures 23 are plate-shaped members having a first attractionface 23 b and a second attraction face 23 c; two hinge arms 23 a and twolevers 23 d extending therefrom are provided at the inner end, and tworollers 37 are rotatably and axially supported at the outer end. A fixedshaft 38 is press-fitted into the four mounting arms 27 a of the insideblock member 27 of the first electromagnets 21, and the total of fourhinge arms 23 a of the armatures 23 and four hinge arms 34 a of theinside block member 34 of the second electromagnets 22 are fitted aroundthe outer periphery of the fixed shaft 38 in a relatively rotatablemanner. The armatures 23 and the second electromagnets 22 are thereforepivotably supported so that they can swing around the fixed shaft 38independently from each other. The fixed shaft 38 referred to here meansthat its position does not move relative to the cylinder head 11, and itmay rotate at the same position.

Two link arms 39 a provided on a control shaft 39 rotatably supported onthe cylinder head 12 and the outside block member 28 of the secondelectromagnets 22 are pivotably supported at opposite ends of a controllink 40 via pins 41 and 42 respectively. Therefore, when the controlshaft 39 is rotated to-and-fro by means of an actuator 43 such as anelectric motor, it makes the second electromagnets 22 swing around thefixed shaft 38 via the control link 40. In this way, since the end partof the second electromagnets 22 that is distant from the fixed shaft 38is driven by the actuator 43, not only is it possible to employ anactuator 43 that has a low output, but it is also possible to suppressrattling of the second electromagnets 22 around the fixed shaft 38.

A first valve spring 47 is provided in a compressed state between anupper face of the cylinder head 12 and a spring seat 46 provided at theupper end of the stem 18 of the intake valve 17. The first valve spring47 urges the intake valve 17 in a valve-closing direction (upward), andthe urging force makes the upper end of the stem 18 of the intake valve17 abut against a lower face of the roller 37 of the armature 23 via alash adjuster 145. Furthermore, a hydraulic cushion mechanism 148provided on the cylinder head 12 abuts against an upper face of theroller 37 of the armature 23.

A base end of a guide rod 150 is pivotably supported via a pin 149between extremities of the pair of levers 23 d extending from the pairof hinge arms 23 a of each of the armatures 23, and a first spring seat151 is integrally formed with the extremity of the guide rod 150.

On the other hand, two squared U-shaped second spring seats 152 arepivotably supported via two pins 54 and 54 between the two pairs oflevers 34 c extending from the two pairs of hinge arms 34 a of theinside block member 34 of the second electromagnets 22, and two of theguide rods 150 run loosely through guide holes 152 a formed in themiddle of the second spring seats 152. One end of a second valve spring153 provided in a compressed state so as to be fitted around the outerperiphery of the guide rod 150 abuts against the first spring seat 151,and the other end abuts against the second spring seat 152. Since thesecond valve spring 153 is supported on the outer periphery of the guiderod 150, not only is the structure compact, but it is also possible tostabilize the shape of the second valve spring 153, thus reliably urgingthe first and second spring seats 151 and 152.

A spring guide 55 is fixed to an upper face of the inside block member27 of the first electromagnets 21 via two bolts 56 and 56, and the twosecond valve springs 153 and 153 are slidably fitted into two springguide holes 55 a and 55 a formed in the spring guide 55. When the axisof the pin 149 coincides with the axes of the pins 54 and 54, the guiderod 150 swings around the pin 149 and the second spring seat 152 swingsaround the pins 54 and 54 at the same time, and there is a possibilitythat the position of the second valve spring 153 will not be defined,but by restricting the positions of the second valve springs 153 and 153by means of the spring guide holes 55 a and 55 of the spring guide 55the above-mentioned problem can be solved.

The operation of the second embodiment of the present invention havingthe above-mentioned arrangement is now explained.

When the second electromagnets 22 are made to swing around the fixedshaft 38 via the control shaft 39 and the control link 40 by theactuator 43, the angle formed between the lower face of the firstelectromagnets 21 fixed to the cylinder head 12 and the upper face ofthe second electromagnets 22 that have been made to swing changes. FIG.12 (A) corresponds to a case in which the angle is a small angle α andthe intake valve 17 is driven with a small amount of lift, and FIG. 12(B) corresponds to a case in which the angle is a large angle β and theintake valve 17 is driven with a large amount of lift.

When the first and second electromagnets 21 and 22 are not energized,regardless of whether the second electromagnets 22 are in a low liftstate or in a high lift state, the armature 23 always stops at asubstantially neutral position of the wedge-shaped space formed betweenthe first and second electromagnets 21 and 22. The reason therefor is asfollows.

In the low lift state, the armature 23 is pushed upward by the stem 18of the intake valve 17, which is pushed upward by the first valve spring47. On the other hand, the guide rod 150, which has the first springseat 151 pushed by means of the one end of the second valve spring 153that has its other end supported on the second spring seat 152 of thesecond electromagnets 22, increases in the amount by which it projectsfrom the guide hole 152 a of the second spring seat 152, and thearmature 23 is urged downward around the fixed shaft 38, that is, urgedso as to push down the stem 18 of the intake valve 17. In this way, byadjusting so that the resilient force of the first valve spring 47urging the intake valve 17 toward the valve-closing direction balancesthe resilient force of the second valve spring 153 urging it toward thevalve-opening direction, the armature 23 stops at a neutral positionthat is substantially midway between the first and second electromagnets21 and 22.

When the second electromagnets 22 descend from this state to the highlift state via the control shaft 39 and the control link 40, which areoperated by the actuator 43, as shown in FIG. 12 (B), the lever 34 dintegral with the second electromagnets 22 swings around the fixed shaft38 in the clockwise direction and compresses the other end of the secondvalve spring 153 via the second spring seat 152 provided on the lever 34d. The guide rod 150 is then pushed upward together with the firstspring seat 151 abutting against the one end of the second valve spring153, and the armature 23 having the lever 23 d pulled by the guide rod150 swings downward around the fixed shaft 38.

As a result, the roller 37 of the armature 23 pushes down the upper endof the stem 18 of the intake valve 17, thus opening the intake valve 17while compressing the first valve spring 47. In this process, since theresilient force of the compressed first valve spring 47 that pushes upthe intake valve 17, that is, the armature 23, and the resilient forceof the compressed second valve spring 153 that pushes down the armature23 are balanced, in this high lift state also the armature 23 stops at aneutral position that is in substantially the middle of the spacebetween the first and second electromagnets first and secondelectromagnets 21 and 22.

When the engine is stopped in a state in which the second electromagnets22 are swung downward in order to change the valve lift, if the armature23 does not stop at the neutral position that is in substantially themiddle of the space between the first and second electromagnets firstand second electromagnets 21 and 22 but is at a position at which it isin contact with the first electromagnets 21, in a cylinder with a timingin which at the moment of starting the engine the second electromagnets22 are energized and the armature 23 is attracted, a large attractionforce would be required for the second electromagnets 22, which are atan increased distance from the armature 23, and problems such as anincrease in the dimensions of the second electromagnets 22 and anincrease in power consumption would occur.

In contrast thereto, in the present embodiment, since the armature 23reliably stops substantially midway between the first and secondelectromagnets 21 and 22 when the engine stops, whichever of the firstand second electromagnets 21 and 22 are first energized when the engineis started, an especially large attraction force is not required, andthe above-mentioned problems are therefore eliminated.

When the first electromagnets 21 are energized, a first attraction face23 b of the armature 23 is attracted to the lower face of the firstelectromagnets 21, and the armature 23 is thereby swung upward aroundthe fixed shaft 38 while compressing the second valve spring 153, and atthe same time as this, the intake valve 17, whose stem 18 is pushedupward by means of the resilient force of the first valve spring 47, isseated on the valve hole 16 and closed. The impact at the moment whenthe intake valve 17 is seated on the valve hole 16 is cushioned by thehydraulic cushion mechanism 148, and the intake valve 17 is seated onthe valve hole 16 by means of the lash adjuster 145 in a state in whichthe first attraction face 23 b of the armature 23 is in intimate contactwith the lower face of the first electromagnets 21.

When the first electromagnets 21 are de-energized and the secondelectromagnets 22 are energized in a state in which the intake valve 17is closed, a second attraction face 23 c of the armature 23 is attractedto the upper face of the second electromagnets 22. The armature 23swings downward around the fixed shaft 38 and pushes the stem 18downward via the roller 37 while compressing the first valve spring 47and expanding the second valve spring 153, thus opening the intake valve17. When the second attraction face 23 c of the armature 23 comes intointimate contact with the upper face of the second electromagnets 22,the amount of lift of the intake valve 17 becomes a maximum amount oflift, and as shown in FIG. 13 the maximum amount of lift is freelychanged by the swing position of the second electromagnets 22.

Since the second electromagnets 22 and the armature 23 swing around thecommon fixed shaft 38, in both the low lift state of FIG. 13 (A) and thehigh lift state of FIG. 13 (B), the second attraction face 23 c of thearmature 23 can be made to come to intimate contact with the upper faceof the second electromagnets 22, and it becomes easy to control theupper face of the second electromagnets 22 and the second attractionface 23 c of the armature 23. Furthermore, since the fixed shaft 38 isprovided on the first electromagnets 21, which are fixed to the cylinderhead 12, not only is it unnecessary to ensure a location on the cylinderhead 12 for providing the fixed shaft 38, but also the positionalrelationship between the first electromagnets 21 and the armature 23 isstabilized, and control of the lower face of the first electromagnets 21and the first attraction face 23 b of the armature 23 becomes easy.

In this way, by changing the swing position of the second electromagnets22, the maximum amount of lift of the intake valve 17 can be variedfreely, and by changing the timing with which the first and secondelectromagnets 21 and 22 are energized and de-energized, the valvetiming of the intake valve 17 can be varied freely. In this process,since only the position of the second electromagnets 22 need be changed,without the positions of the first electromagnets 21 and the armature 23being changed, compared with an arrangement in which all of the firstand second electromagnets 21 and 22 and the armature 23 are moved, theelectromagnetic valve operating device 20 can be made more compact.Moreover, since the first electromagnets 21, which restrict the valveclosing position of the intake valve 17, are fixed so that they cannotmove, the intake valve 17 can be seated with good precision.

Furthermore, the second valve spring 153 is conventionally disposed on aline extended from the first valve spring 47 on the outer periphery ofthe stem 18 of the intake valve 17, but in the present embodiment sincethe second valve spring 153 is moved toward the fixed shaft 38 side, itis unnecessary to ensure that there is space for the second valve spring153 to be disposed on a line extended from the stem 18, and theelectromagnetic valve operating device 20 can be made compact.Furthermore, since parts of the lever 23 d of the armature 23 and thelever 34 c of the second electromagnets 22 overlap when viewed in thecylinder line direction (see FIG. 12 and FIG. 13), the electromagneticvalve operating device 20 can be formed more compactly.

Embodiments of the present invention are explained above, but thepresent invention may be modified in a variety of ways as long as themodifications do not depart from the spirit and scope thereof.

For example, in the embodiments, the present invention is applied to theintake valve 17, but it may be applied to an exhaust valve.

Furthermore, in the embodiments, among the first and secondelectromagnets 21 and 22, only the second electromagnets 22 are made toswing, but both the first and second electromagnets 21 and 22 may bemade to swing.

Moreover, in the embodiments, the pair of armatures 23 are driven withthe same timing and amount of lift, but the armatures 23 may be drivenwith different timings and amounts of lift for each intake valve 17.

1. An engine electromagnetic valve operating device comprising anarmature having one end pivotably supported on an engine main body so asto be capable of swinging and having the other end abutting against astem of a valve, a first electromagnet that can attract a firstattraction face of the armature, and a second electromagnet that canattract a second attraction face of the armature, at least oneelectromagnet of the first and second electromagnets being supported soas to be capable of swinging around a fixed shaft whose position isfixed relative to the engine main body.
 2. The engine electromagneticvalve operating device according to claim 1, wherein said oneelectromagnet causes the valve to lift, and defines the amount of liftof the valve.
 3. The engine electromagnetic valve operating deviceaccording to claim 1 or claim 2, wherein the device comprises a pair ofvalve springs for urging the armature to a neutral position, a springseat supporting one valve spring being fixed to the engine main body anda spring seat supporting the other valve spring moving in response toswinging of said one electromagnet.
 4. The engine electromagnetic valveoperating device according to claim 3, wherein said other valve springand the spring seat supporting the valve spring are disposed on theouter periphery of the stem of the valve, and the spring seat isintegrally connected to and moves with said one electromagnet.
 5. Theengine electromagnetic valve operating device according to claim 1 orclaim 2, wherein the armature is pivotably supported via the fixedshaft.
 6. The engine electromagnetic valve operating device according toclaim 5, wherein the other electromagnet of the first and secondelectromagnets is provided with a fixing part for fixing the fixedshaft.
 7. The engine electromagnetic valve operating device according toclaim 1, wherein the device comprises a first valve spring for urgingthe valve in a valve-closing direction and a second valve spring forurging the valve in a valve-opening direction, the second valve springurging a lever provided on said one end side of the armature.
 8. Theengine electromagnetic valve operating device according to claim 7,wherein said one electromagnet comprises a lever provided on one endside via which the electromagnet is pivotably supported on the fixedshaft, an urging force of the second valve spring on said one end sideacting on the lever of the armature, and an urging force of the secondvalve spring on the other end side acting on the lever of said oneelectromagnet.
 9. The engine electromagnetic valve operating deviceaccording to claim 8, wherein at least parts of the lever of thearmature and the lever of said one electromagnet overlap when viewed ina cylinder line direction.
 10. The engine electromagnetic valveoperating device according to claim 7 or claim 8, wherein a guide rodhaving one end pivotably supported on the lever of the armature andhaving a first spring seat provided at the other end runs through asecond spring seat provided in the lever of said one electromagnet, andone end and the other end of the second valve spring supported on theouter periphery of the guide rod abut against the first spring seat andthe second spring seat respectively.
 11. The engine electromagneticvalve operating device according to claim 8 or claim 9, wherein anactuator making said one electromagnet swing drives the other end sideof the electromagnet.
 12. The engine electromagnetic valve operatingdevice according to claim 3, wherein the armature is pivotably supportedvia the fixed shaft.
 13. The engine electromagnetic valve operatingdevice according to claim 4, wherein the armature is pivotably supportedvia the fixed shaft.
 14. The engine electromagnetic valve operatingdevice according to claim 10, wherein an actuator making said oneelectromagnet swing drives the other end side of the electromagnet.